A detailed examination of the mechanism of bacterial adherence to animal cell components is proposed with two major objectives in mind: i) To delineate the role of lectins in bacterial adherence and to establish their function in the process of cell surface carbohydrate recognition. The study will focus on structural requirements for lectin-ligand interaction with special emphasis on soluble ligands and their potential role as inhibitors. Modification of animal cell surface recognition signals by the action of glycohydrolases such as neuraminidase which are produced by bacteria will be examined. It is the purpose of these studies to determine the molecular events in carbohydrate mediated bacterial adhesion and to establish the limits of this type of cellular recognition under physiological conditions. ii) To examine molecular events between bacteria and cell surface components independent of carbohydrate mediated processes. It is proposed that the surface components that promote bacterial adhesion be isolated by monitoring adhesion with appropriate screening procedures. This will be followed by a chemical characterization and identification of these components. First, the study of bacterial adhesion processes - mentioned above in i) and ii) - is planned to be carried out separately. Later, an effort will be made to understand the way in which these processes work in concert, and the relative importance of each process under physiological conditions.